Experimental and theoretical analysis of core-to-core coupling on fiber bundle imaging
Experimental and theoretical analysis of core-to-core coupling on fiber bundle imaging
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DOI：
10.1364/oe.16.021598
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发表时间：
2008-12-22
期刊：
影响因子：
3.8
通讯作者：
Xu, Chris
中科院分区：
文献类型：
--
作者：
Chen, Xianpei;Reichenbach, Kristen Lantz;Xu, Chris
柔性内窥镜通常使用具有高芯密度的相干光纤束以促进体内成像。期望小的、紧密间隔的芯以在小直径光纤束中实现高数量的可分辨像素。另一方面，紧密间隔的芯潜在地导致强的芯到芯耦合。基于数值模拟，先前解释了图像光纤束可以成功地传输图像，因为芯尺寸的不均匀性降低了耦合。在本文中，我们数值和实验表明，由于结构的不均匀性的随机性，显着的核心到核心的耦合仍然存在于光纤束，通常用于成像。耦合高度依赖于照明波长和偏振状态。我们进一步表明，通过光纤束实现的分辨率不仅取决于核心密度，但也对芯间耦合强度。最后，我们提出，增加芯-包层折射率对比度是一种很有前途的方法，以实现光纤束的低芯耦合，高芯密度，并有效地在单个芯单模传播。(C)2008年美国光学学会
Flexible endoscopes commonly use coherent fiber bundles with high core density to facilitate in vivo imaging. Small, closely spaced cores are desired for achieving a high number of resolvable pixels in a small diameter fiber bundle. On the other hand, closely spaced cores potentially lead to strong core-to-core coupling. Based on numerical simulations, it was previously explained that image fiber bundles can successfully transmit images because of nonuniformities in the core size that reduce coupling. In this paper, we show numerically and experimentally that, due to the randomness of the structural nonuniformity, significant core-to-core coupling still exists in fiber bundles that are routinely used for imaging. The coupling is highly dependent on the illumination wavelength and polarization state. We further show that the resolution achievable by a fiber bundle depends not only on the core density, but also on the inter-core coupling strength. Finally, we propose that increasing the core-cladding index contrast is a promising approach to achieve a fiber bundle with low core coupling, high core density, and effectively single moded propagation in individual cores. (C) 2008 Optical Society of America